This article discusses, the addictive behaviors in the context of DSM-5. The term addiction holds significance for patients, clinicians, researchers, policy makers and many other groups of people. The term "addiction" originated in Roman times and initially was not linked to substance use. However, over time, the term addiction became increasingly linked to substance use such that around the time of DSM-III-R, the committee working on substance-related disorders believed that addiction was defined by compulsive drug use. The DSM-5 process involved multiple research workgroups that convened prior to the operation of the committees. Two research workgroups, one focusing on substance-related disorders and the other on obsessive-compulsive-spectrum disorders, considered how pathological gambling might be considered from a classification perspective, with manuscripts emanating from each workgroup. On the basis of research demonstrating clinical, phenomenological, genetic, neurobiological and other similarities between gambling and substance use disorders, a decision was made to group pathological gambling with substance-related disorders in DSM-5. The inclusion of specific diagnostic criteria for this disorder should help advance clinical and research efforts into its prevalence and impact, and thus its inclusion in DSM-5 represents a significant advance.